1. Field of the Invention
This invention relates to improvements in roller grinders provided with a combination air seal and lubrication system.
2. Description of the Prior Art
It is commonly accepted that pulverizer or roller type grinding apparatus handles materials which upon being reduced create a condition in the pulverizing chamber in which the air is filled with particles thrown about at sufficient velocity to work into the moving parts of the apparatus and accelerate wear. This is especially true of roller grinders in which the grinding rolls must roll freely on the bull ring if proper reduction of the material is to be achieved. Should the particles filling the pulverizing chamber be particularly abrasive, the bearings wear rapidly and cause the grinding rolls to stick or freeze so that the rolls wear in flat spots and reduce the normal output.
The general character of roller grinding apparatus which is related to the present invention is disclosed in the prior patents of Williams U.S. Pat. Nos. 3,337,142 of Aug. 22, 1967, and 4,022,387 of May 10, 1977. Neither of these patents have disclosed any provisions for protecting the bearings. It is of course understood that air sealing of bearings and lubricant means have been utilized in separate systems which do not allow for indicating the on-set of bearing failure or actual bearing failure. When bearing failure does occur, the apparatus must be shut down quickly and dismantled for repair. This shut down event takes an expensive piece of equipment out of production and on occasions replacement parts are not readily at hand to resume productivity.
The problem in roller grinding apparatus is in finding a way of monitoring the bearings for wear and failure of lubrication and seals for the bearings, and determining the on-set of failure. As pointed out the critical bearings are associated with rapidly rotating components and in an atmosphere highly charged with dust, dirt and abrasive particles.